Why Mount Rainier Volcano Still Remains a Great Threat?
Mighty Mount Rainier
Mount Rainier, a volcanic mountain, in Washington State, has been a cause of concern for authorities, for many decades. The mountain's potential for damage scares experts, CNN reported. The various communities residing around the mountain are in constant danger of the "lahar" that the peak could produce if it erupts. "Mount Rainier keeps me up at night because it poses such a great threat to the surrounding communities. Tacoma and South Seattle are built on 100-foot-thick (30.5-meter) ancient mudflows from eruptions of Mount Rainier," Jess Phoenix, a volcanologist and ambassador for the Union of Concerned Scientists, said about the snowcapped peak.
The Present State of Mount Rainier
Mount Rainier has not had a substantial eruption in the last 500 years, USGS reported. Experts still consider it to be potentially the most dangerous volcano in the Cascade Rang. They cite the mountain's great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle as reasons behind their concern. Currently, the mountain has 25 major glaciers which contain five times more snow and ice than all the other volcanoes situated in Cascade combined. Researchers claim that even if a small part of the ice present at Rainier melts down due to volcanic activity, there would be enough water accumulated to trigger the dangerous "lahar."
Lahar
Lahar is a slurry of water and volcanic rock coming from ice or snow that swiftly travels through valleys and drainage channels. While flowing through the valleys and drainage channels, the slurry picks up debris and can cause huge damage if it enters human habitation. "The thing that makes Mount Rainier tough is that it is so tall, and it’s covered with ice and snow, and so if there is any kind of eruptive activity, hot stuff… will melt the cold stuff and a lot of water will start coming down,” said Seth Moran, a research seismologist at USGS Cascades Volcano Observatory in Vancouver, Washington. "And there are tens, if not hundreds of thousands of people who live in areas that potentially could be impacted by a large lahar, and it could happen quite quickly."
Past Eruptions of Mount Rainier
As per experts, lahars occur during volcanic eruptions and are caused by landslides and earthquakes. Geologists have found evidence of at least 11 lahars from Mount Rainier reaching the surrounding Puget lowlands, in the past 6,000 years. Scientists have not connected the most recent of these lahars, which occurred around 500 years ago, to any volcanic activity and instead associated it with the landslides on the mountain’s west flank. Volcanologists believe that it is not far-reaching to assume that such a landslide could happen again and trigger a lahar. "There’s the knowledge now that the volcano is potentially capable of doing it again. And then we’re in this world of it could happen at any time," Moran said. "Should it be the same size, then it’s 10 minutes to the nearest places where people are living, and 60 minutes to the nearest large communities. And those are really short time frames," he added.
Damage Caused by Lahar
A 2022 study analyzed the potential damage that could be caused by a lahar from Mount Rainier, CNN reported. The study claims that a lahar originating from the west side of Mount Rainier could produce debris equivalent to 104,000 Olympic-size pools overwhelming the population of Orting, Washington, about one hour after an eruption. Another area that could be in danger, as per the study, is the Nisqually River Valley, where the lahar could cause water from Alder Lake to spill Alder Dam, and cause damage to human lives and infrastructure.